Online X-ray radiation dose optimization in repeat CT scanning

Computer Tomography (CT) is nowadays pervasive and plays a central role in all aspects of patient care. The main disadvantage of CT imaging is that it exposes thepatient to a substantial amount of ionizing radiation may be harmful to the patient. Much research has been recently devoted to develop methods to achieve diagnostic imagequality with the lowest possible radiation dose. Repeat CT scanning, in which a patient is scanned some time after a baseline scan was acquired, presents significant, untappedopportunities for dose reduction and optimization.

In this talk, we will present a new computational paradigm for on-line radiation dose optimization in repeat CT scanning. The key principle is to use the information of thebaseline scan during repeat scanning to significantly reduce the radiation dose without image quality loss. Our approach is unique in that it formulates radiation dose reductionas an adaptive sinogram construction optimization problem in 3D Radon space instead of an image reconstruction problem in image space. We will describe novel methods forregistration of the baseline scan to the patient, for low-dose repeat scanning with no information loss, and for and needle tracking in interventional CT.